The present invention relates generally to off-road motor vehicles, such as utility or recreational vehicles, and more particularly, to an adjustable bogey beam support apparatus for the front and middle axles of a utility vehicle to vary the distribution of load between the front and middle axles.
Small off-road vehicles such as utility or recreational vehicles are becoming popular for recreational and other general purpose off-road usage. Such utility vehicles can be found in U.S. Pat. No. 4,706,770. These utility vehicles have found usage on golf courses and at sporting events, and are particularly adaptable for utilization on a farm. This type of flexibility in the wide variety of uses necessitates a vehicle that is highly flexible, highly maneuverable and the like. This demands a vehicle that will afford a high degree of maneuverability and ease of steering.
Steering characteristics of known utility vehicles provide poor turning performance. Known utility vehicles have turning clearance circles having a diameter greater than twenty-one feet. The use of independent front wheel suspension mechanisms on known utility vehicles, coupled with the mounting of the rack and pinion systems on the frame of the vehicle, introduces minor king pin rotations as the steering tires ride over ground undulations. Such construction reduces steering precision and can accelerate the wear of the tires on the steering axle.
Placing a load on the utility vehicle typically results in a variation in the steering performance of known utility vehicles. For example, one known embodiment having a front steering axle, a rear drive axle, and a middle drive axle carries the load placed on the vehicle on the middle and rear axles, resulting in proportionately less weight on the steering axle and a reduction in maneuverability. Accordingly, known utility vehicle construction results in a significant influence on the steering performance by the load carried on the vehicle. Preferably, loads should not change the steering characteristics for any vehicle.
Furthermore, conventional utility vehicle construction mounts the middle axle directly to the frame of the vehicle, resulting in a harsh ride characteristic and direct application of any load placed into the load bed onto the middle axle as well as the rear drive axle. It would, therefore, be desirable to enhance the ride characteristics, as well as the steering performance of utility vehicles by distributing the weight of the loads being carried in a different manner.
Steering characteristics can be varied by changing the load applied to the front and middle axles. Depending on the steering characteristics desired by the operator, it would be advantageous to be able to vary the proportional distribution of the load applied to the front and middle axles.
It is therefor desirable to provide a utility and recreational vehicle that overcomes the disadvantages of the known prior art utility vehicles.
Accordingly, an important object of the present invention is to provide a middle axle for a utility vehicle that is not directly mounted to the frame of the vehicle.
It is another object of this invention to provide a bogey beam apparatus for supporting the front and middle axles on a utility vehicle.
It is a further object of this invention to provide support for the middle axle of a utility vehicle in such a manner as to prevent the load placed thereon from overcoming the steering operation of the front axle.
It is a feature of this invention to add a bogey beam extending longitudinally at the center line of the utility vehicle to interconnect the front and middle axles.
It is another feature of this invention that a portion of the load placed into the load bed of the utility vehicle will be distributed to the bogey beam to be re-distributed to the front and middle axles in a predetermined proportion.
It is still another object of this invention to provide an adjustable pivot mechanism for the bogey beam to vary the proportional loading between the front and middle axles.
It is still another feature of this invention that the proportional loading between the front and middle axles can be varied at the discretion of the operator.
It is an advantage of this invention that maneuverability of the utility vehicle is preserved during load bearing operations.
It is another advantage of this invention that the steering characteristics of a utility vehicle can be adapted to the desires of the operator by changing the proportional loading between the front and middle axles.
It is still another advantage of this invention that the ride characteristics-of a utility vehicle are improved, particularly under load bearing conditions.
It is still another feature of this invention that the loads placed on the load bed of the utility vehicle are proportionally distributed between the front steering axle and the middle drive axle of the utility vehicle.
It is a further object of this invention to provide a bogey beam mechanism for an off-road vehicle that is durable in construction, inexpensive to manufacture, carefree in maintenance, easy to assemble, and simple and effective in use.
These and other objects, features, and advantages are accomplished according to the present invention by providing a utility vehicle having a bogey beam on which are mounted the steering axle at the forward end of the bogey beam and the middle axle on the rearward end of the bogey beam. A rear drive axle is supported directly on or suspended from the frame of the utility vehicle. The bogey beam can be rigidly or resiliently connected to the frame by a pivot assembly defining a transverse pivot axis about which the bogey beam can oscillate. The weight transferred to the bogey beam is proportionately distributed between the front steering axle and middle axle. As a result the steering characteristics of the steering axle are not impaired by the imposition of a load in the load bed of the utility vehicle, as the middle axle cannot be loaded sufficiently to overpower the front steering axle. The bogey beam is provided with a plurality of pivot axis locations to vary the proportions of the load applied to the front and middle axles as a result of the longitudinal movement of the bogey beam pivot.